The Achilles heel of Docker is not caching all artifacts. There needs to be a --cache-only option where it pulls packages to the host then copies them into the

The Achilles heel of Docker is not caching all artifacts. There needs to be a --cache-only option where it pulls packages to the host then copies them into the container. Right now you have to do a two container build where the first pulls packages, you copy them out for archival/caching, then copy them into a second container for the build. I guess another solution would be to have the base container pull the packages but not install anything. The child container would actually do the build then clean up.